Charles turnbull



(No Model.)

0. TURNBULL, Jr. ELECTRIC BELL.

No. 513,220. Patented Jan. 23, 1894.

I Awezofar UNITED STATES PATENT OFFICE.

CHARLES TURNBULL, J R., OF NORTH SHIELDS, ENGLAND.

ELECTRIC BELL.

SPECIFICATION forming part of Letters Patent No. 513,220, dated January 23, 1894.

Application filed November 11. 1893- Serial No. 490,634:- (No model.)

To all whom it may concern.-

Be it known that 1, CHARLES TURNBULL, Jr., a subject of the Queen'of Great Britain and Ireland, and a resident of North Shields, county of Northumberland, England, have invented certain Improvements in the Construction of Electric Bells, of which the following is a specification.

This invention refers to improvements in the construction of electric bells and consists in a special combination of parts having for its object an improved regulation or adjustment of the period of electrical contact whereby improved results may be obtained from the bell.

The accompanying drawings in which Figure 1 shows a front elevation and Fig. 2 an under side plan view of the same illustrate one method of effecting myinvention, and in the following description like marks of reference designate like parts.

Referring to the drawings a represents an electrical magnet mounted on a wooden frame a, and a is the armature hinged at a in bracket 1). The arm or extension of the armature, it will be observed, is pivoted to the v hammer bar 8 (to which is fixed the hammer 9) at N; and P is a fixed pin or fulcrum (and also a terminal) where make-and-break of contact is effected.

10 is a gong bell.

B represents the battery, P and T the terminals and T the wires leading from the battery around the magnet and thence when the circuit is completed through bracket 1), armature a extension at and the part N E of hammer bar 8. Thus when the armaturestrikes the magnet, the contact is broken by the momentum in hammer causing end E to depart from P, the rebound of the hammer causing the contact between E and P to be renewed.

It will be observed that in the apparatus described the electrical circuit is not broken until the armature has actually struck the magnet and that the contact must break at this particular point the result of which is that the hammer is thrown against the bell with great force whereas if the contact was broken before 'the armature struck the magnet, the force of the hammer against the bell must be materially reduced. Immediately hammer will hit the hell with very powerful blows, whereas as hitherto constructed increase of battery power has the chief effect of increasing the frequency instead of the actual power of the blows.

The strokes of the bell are by my invention so distinct that the vibration of the gong is not unduly interfered with as in bells hitherto constructed.

'What I claim as my invention, and desire to secure by Letters Patent, is I 1. In electric bell apparatus the combination with an electro-magnet and vibrating armature having a fixed extension 4 thereon the outer end of which is pivoted to an intermediate point N on the hammer bar of a make-and-break point of electrical circuit between the inner or shorter end E of the hammer-bar extension and a pointP to which the circuit wire is connected the several parts being arranged and adapted to operate as set forth.

2. In electric bell apparatus the combina-- tion with an electro-magnet and vibrating armature having a fixed extension 4. thereon, the outer end of which is pivoted to an intermediate point N on the hammer-bar, the travel of the said armature being regulated by screw S, of a make-and-break point of electrical circuit between the inner orshorter end E of the hammer-bar extension and a point P to which the circuit wire is connected the several parts being arranged and adapted to operate as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

THos. HOPPER, E. TURNBULL. 

